There are already a couple of bus operators interested in picking up some of the route Greyhound is casting off.
One is Maritime Bus that took over from Acadian Lines 6 years ago. The owner says he obtained a less onerous operating license in negotiations with the Provinces that now allows him to adjust schedules without going through all the regulatory hearings etc. They can also now cross-subsidize between their other operations: city transit, school bus, charters and multi-day tours. And that is something the western Provinces are going to have to allow if any bus service is going to survive: a less regulated environment.
https://www.cbc.ca/news/business/greyhound-canada-bus-follow-1.4740974
Calgary Edmonton and most of the larger cities in Alberta are already served by another operator besides Greyhound: Red Arrow.
https://www.redarrow.ca/
Calgary Edmonton have always been mentioned as good candidates for high-speed rail but most people today are just out on the Queen Elizabeth II Highway for the 300 kms, 3 hr drive or they are in the air.
As far back as the 1960's when the Edmonton Airport was near the city centre (across from the VIA Station....but now closed) Pacific Western Airlines operated the 'Chieftain Airbus' modeled on the Eastern Shuttle in the US Northeast.....just show up and go.
Today it's not as convenient today to fly as the Edmonton International Airport is farther out of the cityactually on the way to Calgary so when you consider the time you have to be there before your flight you would nearly be in Calgary driving.
PWA's Airbus Timetable from the 1960's: